1. Field of the invention
The present invention relates to bakery foods containing dietary fibers.
2. Description of Prior Art
Recent years, it has been made clear that deficiency of dietary fibers is closely related to certain diseases such as cancer, heart disease, cerebral apoplexy, diabetes each ranking high in the causes of death in western countries as well as in Japan, and to diseases such as constipation, varicocele, cholelithiasis. Under such circumstances, various kinds of foods containing dietary fibers have come to be sold on the market in conjunction with the recent change in eating habits. Representative ones among the mentioned foods containing dietary fibers are soft drinks, desserts, teas, starch noodle (glass noodle), soybean curd (tofu), etc. It is, however, hard to take in quantitatively a required amount of dietary fibers from such foods in the eating habits today, and therefore it is desired to prepare daily foods so as to contain quantitatively required amount of dietary fibers. It may be generally said that bakery foods such as bread is certainly suitable to be employed as one of the mentioned dietary fiber foods, but various disadvantages come out when adding the dietary fibers to the bakery foods mainly from the viewpoint of quality.
The dietary fibers are roughly classified into water-soluble dietary fibers and insoluble ones. Cellulose, lignin, hemicellulose A and C, chitin, collagen, etc. belong to the latter. The former is further divided into high molecular materials such as pectin, guar gum, devils-tongue mannan, sodium alginate, carrageenan, agar, carboxymethylcellulose, etc. and low viscosity materials such as indigestible dextrin, polydextrose, etc.
When adding some insoluble dietary fibers to a bakery food such as bread, one who eats the food feels rough to his tongue due to the insolubility, resulting in an undesirable taste. On the other hand, this disadvantage of feeling rough to one's tongue is certainly overcome in the case of water-soluble dietary fibers, but in the group high molecular materials being one of such water-soluble dietary fibers, viscosity is high and water absorption coefficient of "dough" is increased. Accordingly, when adding a high molecular material over 3%, extensibility of dough is reduced thereby causing a difficulty in formation of dough. As a result, it becomes unavoidable to add more water for overcoming such difficulty, which, in turn, brings about a taste different from familiar one, and moreover there arises another problem of increasing water activity and accelerating deterioration (i.e., life of the food).
In the case of adding low viscosity materials, although there is no problem like the addition of high molecular materials, volume of the product obtained is reduced eventually resulting in a disadvantage of tastelessness.
It is expected that dietary fibers perform various useful physiological functions such as reduction of cholesterol, saving the insulin secretion, acceleration of bowels evacuation, saving of harmful objects, etc. and are now occupying a position of 6th nutritive substance. However, due to the change of the eating habit in recent years, amount of dietary fibers taken in from the daily meals has been actually reduced, and hence it is desirable to have meals containing more dietary fibers from the viewpoint of preventive medicine.